An interesting WebmasterWorld thread touches on an expert topic of "account wide" quality score. What this AdWords professional is scared of is to start a new campaign within the same account, in fear that the new campaign will hurt his account wide quality score.

So this advertiser is holding back spending more money with Google, because of the fear that in doing so, his older ads will cost more and rank lower. He said:

I really want to spend more with Google, but I daren't!

This sprung AdWordsAdvisor's interest:

This is an important topic, dmorison, and I thank you for starting the thread.

Was it the "account wide" quality score that made it an important topic or the fact that he and possibly other advertisers are fearful of spending more money with Google due to the quality score?

Of course, the advertiser can set up a totally new account under a new credit card and email, if they want to keep them completely separate. Or they can create clients and manage them under your My Client Center.

Are you afraid of setting up new campaigns because of it having the potential of hurting your quality score?